Systems and methods of phase-locked loop involving closed-loop, continuous frequency range, auto calibration and/or other features

Abstract

Systems and methods involving phase-locked-loop (PLL) circuitry are disclosed. In one illustrative implementation, a PLL circuit device may comprise voltage controlled oscillator (VCO) circuitry having a bias signal that sets a frequency range, circuitry that shifts the VCO circuitry to operate in one of the frequency ranges, and other circuitry to compare/calibrate signals and/or set the bias current. According to further implementations, as a function of operation of the circuitry, an operating frequency range of the VCO circuitry may be shifted to a different operating frequency range, and closed-loop, continuous frequency range, auto-calibration or other features may be provided.

The invention claimed is: 
     
       1. A method of controlling a voltage controlled oscillator (VCO), comprising:
 determining whether an input voltage to the VCO is within a desired range; 
 generating a shift signal that shifts a current operating frequency range of the VCO to a different operating frequency range of the VCO when the input voltage is not within the desired range; 
 shifting a counter up or down in response to the shift signal; 
 generating a control signal corresponding to the shifted counter; and 
 changing the operating frequency range of the VCO by changing a bias current of the VCO based on the shift signal to change the operating frequency range of the VCO to the different operating frequency range of the VCO. 
 
     
     
       2. The method of  claim 1 , further comprising generating an indication that the input voltage is not within the desired range when the input voltage is not within the desired range. 
     
     
       3. The method of  claim 2 , wherein the indication indicates whether the input voltage is above or below the desired range. 
     
     
       4. The method of  claim 1 , further comprising generating a shift instruction when the input voltage is not within the desired range. 
     
     
       5. The method of  claim 1 , wherein:
 the determining whether the input voltage is within a desired range comprises determining whether the input voltage is above or below the desired range; 
 the shift instruction comprises an instruction to shift up when the input voltage is above the desired range; and 
 the shift instruction comprises an instruction to shift down when the input voltage is below the desired range. 
 
     
     
       6. The method of  claim 1 , wherein the determining whether the input voltage is within a desired range comprises determining whether the input voltage is above or below the desired range. 
     
     
       7. The method of  claim 6 , wherein changing the OFR of the VCO comprises:
 changing the OFR of the VCO from a current one of the plurality of OFRs to a higher one of the plurality of OFRs when the input voltage is above the desired range; and 
 changing the OFR of the VCO from a current one of the plurality of OFRs to a lower one of the plurality of OFRs when the input voltage is below the desired range.